In Sight of the Lord: Part 1 (S04E01)

The case of an ex-soldier found dead with his skull nailed to the floor in 1948 has been reopened due to media attention and pressure created by his grandson. The team discover a similar murder dating back to the 1960s. Then the killer strikes again and a further victim is found nailed to the floor - this time in a nursing home for the elderly. Is World War II the common link? The team must find the next possible victim, but no one knows where he is. (iTunes)